The invention relates to hydraulically actuated control valves used to regulate water flow through water supply pipes in irrigation systems. The invention particularly relates to filters on water inlets used to extract water from the water supply pipes for use in hydraulically actuating the control valves.
Supply pipes convey water from a water source, such as a pond or well, to sprinklers, nozzles and water guns arranged along the length of the supply pipe. The supply pipes may have diameters of six to ten inches (152 to 254 millimeters) and a length of as much as a quarter to half a mile (400 to 800 meters) for center pivot irrigation systems.
Water flow through the supply pipes is turned on and off by control valves in the supply pipes. The control valves may also regulate the water pressure in the supply pipes. Control valves may be placed regularly along the length of a supply pipe to control water flow at different locations along the supply pipe and to ensure that the water pressure along the supply pipe is relatively uniform.
The control valves are actuated hydraulically using water extracted from the supply pipe to which the control valves are attached. A difficulty with water in the supply pipe is it has dirt, sand, grasses, starch and other debris (collectively, debris) that comes with the water when pumped into the supply pipe from the water's source. The water source may be drainage ditches in an agricultural field, ponds, streams, wells and other generally dirty sources of water.
Debris can interfere with the operation of the control valve. Specifically, the debris may clog the narrow passages in hydraulic hoses, control solenoid (pressure regulator) and other components that provide hydraulic control of the control valve. To avoid interfering with the operation of the control valve, water extracted from the supply pipe is filtered before flowing into the narrow passages of the hydraulic control system. The filtering of the water results in debris collecting on the outer surface of the filter.
To clean the filter, it is conventional to remove the filter from the control valve. Removal of the filter is time consuming and expensive in that it requires service personnel to travel to the water supply pipe and remove and clean the filter. There is a long-felt need for techniques that reduce the cost and effort needed to maintain an irrigation system.